WASHINGTON — Red Cross investigators concluded last year in a secret report that the Central Intelligence Agency’s interrogation methods for high-level Qaeda prisoners constituted torture and could make the Bush administration officials who approved them guilty of war crimes, according to a new book on counterterrorism efforts since 2001.

The book says that the International Committee of the Red Cross declared in the report, given to the C.I.A. last year, that the methods used on Abu Zubaydah, the first major Qaeda figure the United States captured, were “categorically” torture, which is illegal under both American and international law.

The book says Abu Zubaydah was confined in a box “so small he said he had to double up his limbs in the fetal position” and was one of several prisoners to be “slammed against the walls,” according to the Red Cross report. The C.I.A. has admitted that Abu Zubaydah and two other prisoners were waterboarded, a practice in which water is poured on the nose and mouth to create the sensation of suffocation and drowning.

The book, “The Dark Side: The Inside Story of How the War on Terror Turned Into a War on American Ideals,” by Jane Mayer, who writes about counterterrorism for The New Yorker, offers new details of the agency’s secret detention program, as well as the bitter debates in the administration over interrogation methods and other tactics in the campaign against Al Qaeda.

Citing unnamed “sources familiar with the report,” Ms. Mayer wrote that the Red Cross document “warned that the abuse constituted war crimes, placing the highest officials in the U.S. government in jeopardy of being prosecuted.” Red Cross representatives were not permitted access to the secret prisons where the C.I.A. conducted interrogations, but were permitted to interview Abu Zubaydah and other high-level detainees in late 2006, after they were moved to the military detention center in Guantánamo Bay, Cuba.

The book says the C.I.A. shared the report, which Ms. Mayer first described last year in less detail in The New Yorker, with President Bush and Secretary of State Condoleezza Rice.

Bernard Barrett of the International Committee of the Red Cross declined to comment on the book except to say that the committee “regrets that any information has been attributed to us” because it believes its work is more effective when confidential.

He did confirm that committee personnel “are regularly visiting” the high-level Qaeda prisoners, now at Guantánamo Bay. “We have an ongoing confidential dialogue with members of the U.S. intelligence community, and we would share any observations or recommendations with them.”

The book says Abu Zubaydah told the Red Cross that he had been waterboarded at least 10 times in a single week and as many as three times in a day.

The book also reports that Khalid Shaikh Mohammed, the chief planner of the attacks of Sept. 11, 2001, told the Red Cross that he had been kept naked for more than a month and claimed that he had been “kept alternately in suffocating heat and in a painfully cold room.”

The report says the prisoners considered the “most excruciating” of the methods being shackled to the ceiling and being forced to stand for as long as eight hours. Eleven of the 14 prisoners reported prolonged sleep deprivation, the book says, including “bright lights and eardrum-shattering sounds 24 hours a day.”

Ms. Mayer acknowledges that Red Cross investigators based their account largely on interviews with the prisoners. But she writes that several C.I.A. officers she spoke with confirmed parts of the Red Cross description.

A C.I.A. spokesman, Paul Gimigliano, confirmed that Red Cross workers had been “granted access to the detained terrorists at Guantánamo and heard their claims.” He said the agency’s interrogations were based on “detailed legal guidance from the Department of Justice” and had “produced solid information that has contributed directly to the disruption of terrorist activities.”

“The Dark Side” also describes a frightening false alarm at the White House on Oct. 18, 2001, when, it says, an alarm went off on a machine designed to detect biological, chemical or radiological attacks. According to the book, among those who believed they might have been exposed to a pathogen was Vice President Dick Cheney.

A spokeswoman for Mr. Cheney, Lea Anne McBride, said his office had not seen the book and could not comment. An administration official who spoke on condition of anonymity because the official was not authorized to comment on the issue said aides had investigated the book’s account at Ms. Mayer’s request and that “no one recalls such an incident.”

Correction: July 12, 2008

Because of an editing error, an article on Friday about a new book on American counterterrorism efforts omitted two responses from Bush administration officials to an assertion that Vice President Dick Cheney believed he might have been exposed to a pathogen in October 2001. A spokeswoman for Mr. Cheney, Lea Anne McBride, said the vice president’s office had not seen the book, “The Dark Side: The Inside Story of How the War on Terror Turned Into a War on American Ideals,” by Jane Mayer, and could not comment on it. An administration official who spoke on condition of anonymity said that officials had investigated the book’s claim at Ms. Mayer’s request and that “no one recalls such an incident.”

Because of an editing error, the article also failed to attribute the assertion about Mr. Cheney’s fears; it should have specified that “the book said” that Mr. Cheney was among those who believed he might have been exposed to a pathogen after a false alarm at the White House on Oct. 18, 2001 on a machine designed to detect biological, chemical or radiological attacks.

A version of this article appears in print on , on Page A9 of the New York edition with the headline: Book Reveals Red Cross Report on C.I.A. Torture of Qaeda Prisoners. Order Reprints|Today's Paper|Subscribe